A Russian judge has given prominent opposition leader Alexei Navalny a five year suspended sentence after he was convicted of embezzlement, a decision that may prevent him from running in next year's presidential election.

Navalny, who maintains his innocence, said he would appeal the sentence and would still run for president against Vladimir Putin, should Putin decide to seek another term in office.

"We don't recognize this ruling," Navalny said after he was sentenced. "I have every right to take part in the election, according to the constitution, and I will do so," he added.

Navalny accused Russian government officials of trying to block him from running for president, claiming the sentence was "a message saying that they consider me, my team and the people whose views I'm representing too dangerous to be allowed into the election campaign."

When reporters asked if Navalny's absence from the presidential race would compromise the validity of the election, Kremlin spokesman Dmitry Peskov responded, "We don't believe any concerns about this are appropriate."

The Organization for Security and Co-operation in Europe, a regional security group, expressed concern over the conviction.

"I fear that Alexei Navalny's conviction today is just the latest case of the courts being used to exclude certain individuals from the political arena," said Michael Georg Link, director of the group's Office for Democratic Institutions and Human Rights.

Russian law bars anyone found guilty of committing a "high-level crime," which would include embezzlement, from running for office for 10 years.

Navalny announced in December his intent to run for president in 2018, when Putin's current term expires. He said after the verdict he believed he could still run for office because the 10 year disqualification does not apply to those given a suspended sentence.

The sentence was handed down by a regional judge in the city of Kirov in a retrial that had the same outcome of a 2013 trial.

A U.S. State Department official said the U.S. said the decision appears to be an example of an ongoing crackdown on independent voices by the Russian government.

“The Russian people, like people everywhere, deserve a government that supports an open marketplace of ideas, transparent and accountable governance, equal treatment under the law, and the ability to exercise their rights without fear of retribution,” the official said.

Navalny first became publicly known for exposing fraud in Russian state corporations. He was a leader during protests in 2011 and 2012 that united around Putin's return to the presidency.